1. Field of the Invention
The present invention relates to an evaporation type magnetic recording medium in which data is recorded and reproduced in a serpentine fashion and a magnetic recording and reproducing device for recording and reproducing data on the medium.
2. Description of the Related Art
In recent years, as an amount of data dynamically increases, the capacity of a tape storage system has urgently needed to be increased. In order to realize the increase of the capacity of the tape storage system, a recording density is requested to be improved. Under these circumstances, in what is called a linear type magnetic recording tape system, it has been difficult for a currently used particulate type tape to more improve the recording density. Accordingly, the use of an evaporated tape in future has been investigated. In the linear type system, since the data is recorded and reproduced in the serpentine fashion as described above, when the evaporated tape is used therefor, the directivity of the evaporated tape causes a problem.
In the evaporated tape usually employed in a non-tracking (NT) type digital tape recorder, since a forward and reverse directivity is desired to be low in electromagnetic conversion characteristics, an oblique evaporation layer has a two reverse layer structure as disclosed in patent documents such as Japanese patent Application Laid-Open No. hei 5-182168, Japanese patent Application Laid-Open No. hei 4-353621 and Japanese Patent Application Laid-open No. hei 4-353622. However, under the usual recording density, an inductive MIG (metal in gap) head has been used as a reproducing head. Therefore, in the evaporated tape used therefor, the entire thickness of a magnetic layer is large as thick as 200 nm. Further, the surface property of the tape has been rough and a spacing between the head and the tape has been large.
On the other hand, in a magnetic recording system aiming at a current high recording density, an AMR head (anisotropic magnetoresistive effect head) is used and the thickness of the magnetic layer of a tape is decreased to about ⅓ as thick as a usual thickness. Further, the surface property of the tape is improved and a spacing between the head and the tape is decreased. Accordingly, there is a risk that the design of the thickness of the magnetic layer is different from the usual design of the thickness of the magnetic layer.
In order to improve the recording density in future as described above, the use of a GMR head (giant magnetoresistive effect head), a TMR head (tunneling magnetoresistive effect head), etc. may be thought out from the current AMR head as the reproducing head. However, since a medium to be used therefor is thinner than that for the AMR head, the optimum film forming ratio of the herringbone type dual evaporated layer is more important.